ERD Apps a Missing OSS Niche?

Pennyless Developer asks: "So the time comes when one must design a brand spankin' new database schema. You want to use an Entity-Relationship diagramming tool with hopefully some automatic schema generation tools, but do not have much money to purchase anything like Rational Rose. Like a true geek well versed in OSS, you head off to scan sourceforge, freshmeat, and google. But alas, it appears no such applications exist in the OSS world, at least none beyond the planning stage. The question I pose is this: What useful, OSS/Free/Cheap ERD applications have you found and used? Or do developers do all their ERD work under an evaluation period of commercial software?"

Data Architect from TheKompany

[Anonymous Coward]

If i am understanding your question. This may be something you could use. I do not know if there is a GTK equivalent or if that even matters.

http://www.thekompany.com/products/dataarchitect /

OSS Rational Rose equivalent

[sl956]

If you want an OSS cross-platform replacement of Rational Rose, you should try argoUML [tigris.org] :

• 100% java
• BSD licence
• only a few UML v1.3 features [tigris.org] not (yet) supported
• import/export from/to Rational Rose using XMI are not (yet) totally working but a third party tool exists to do the translation (can't recall the name)
• SVG output (!)
• you can add all the plugins you want/need on top of the core app (MOF metamodel and GEF graphical framework)
• commercial support provided by Gentleware [gentleware.com] (if you've got a PHB to convince)

All in all a very cool app if you need something like Rational Rose.
BUT I'm not aware of any support of Entity/Relationship diagramming or sql generation in either of those apps.

Re:OSS Rational Rose equivalent

[Hektor_Troy]

I haven't looked into the project yet (I'm still at work, and am just inbetween recompiling).

Can ArgoUML create code from sequence diagrams? Partial code?

I haven't found ANY UML tool that can do that, and it's a real pain in the ass to have to reimplement everything you just did in the diagram in code ...

Great tool but not for ERD

[Felipe Hoffa]

ArgoUML is a great tool, but it isn't designed for ER databases. As it name says its for UML, and UML doesn't include an specification for ERD.

You can try faking a class diagram to look as an ERD using some stereotypes, but those stereotypes are not implemented yet in ArgoUML yet (Rational Rose has them).

Anyway, ArgoUML is a great product and I'm a proud user of it.

Fh

Check out Dezign for Databases

[sheraz]

A year ago I hit this wall. I gave up on the OSS end and decided to (gasp) buy a package - Dezign for Databases by a company called Datanamic [datanamic.com]. $150 for the full version - you can use all kinds of DBs - Postgres,Mysql,Oracle,DB2,etc,etc. I will also do Access conversion stuff, but I have never played with that. There is talk that they will release a Linux version. As of now it is only Win32, but it is work every penny. It has saved me tons of time.

DBVisualizer or Visual Thought

[Will Sargent]

A shameless plug for Visual Thought [tersesystems.com]. It won't do ERD automatically, but it's great for the stuff you'd use a whiteboard for usually.

If you want to look at the structure of an existing database, try DBVisualizer [www.minq.se]

dia2sql

[FreakBoy]

I just saw a new package in debian called dia2sql. You may want to check that out...

Tools? Bah....

[ericnewton]

I like to write my ER diagrams in something executable, like python scripts, which will create my schema automagically.

If you gotta have pictures, you might want to check out Dia [lysator.liu.se], whose file format is XML. It has ER diagram components for you to connect. When you are done drawing, write a quick program to translate the XML description into SQL.

Re:Tools? Bah....

[V. Mole]

..write a quick program to translate the XML description into SQL.

No, don't write one, get dia2sql [karyopse.de]

MagicDraw UML

[NeuroMorphus]

Check out MagicDraw UML(http://www.linux.org/apps/AppId_6831.html [linux.org])

But 2 thumbs up for the previous python post that suggest writing python scripts.

Why?

[PersonalizedSpam]

Drop the UML .... drop the "automated schema changes" and use normal, old fashioned oo --> database methodoligies. This whole fixation on UML and autotmated schema creation is just absurd, when its so easy to work with the database itself in sQL ... and won't hamper your design. The managers at my old company loved UML and schema propogation ... and were awarded with bloated, hard to understand code. (Thank God they had no say over my use of the database). My 2 cents ....

Re:Why?

[sidecut]

In my opinion, good automated tools work well for large projects that are hard to code and maintain by hand.

I agree with you that one may have problems understanding and maintaining the detailed code resulting from code builders/generators/etc., but that can result from two things:

1) Generated code is inherently trickier to read than hand-written code. The good code generators amply comment so that you know the difference between what's been generated and what you've coded.

2) Such tools are intended for a higher layer than the code layer (to coin a phrase). An analogy (that stretches the point a little) may help explain what I'm saying: it's similar to reading the assembler output from a good compiler and complaining that it's hard to understand the programmer's intent. Correct! The assembler is not meant to be read; the higher-level source code is the real code.

Such design tools work well if they incorporated good "round-trip engineering," which means you can switch back and forth between the generated code (SQL) and the "source" code (the diagram).

(I hate to say it, but VC++ does a pretty good job of this when writing COM objects. You point and shoot and it creates skeleton code and interface code based upon your declarations, but you may still tweak the hell out of the resulting code. This is because they did a good job of putting markers in the comments.)

If the product being considered has good round-trip engineering or can otherwise track well the code it's generated, I believe you've got the best of both worlds.

Reading the other posts, in my opinion the XML-based package (Dia) rocks (at least on paper -- I've never used it). From the resultant XML a series of good code generators can be written.

Subject for a future Ask Slashdot: what's a good convention for such round-trip comments?

Dia

[autechre]

http://freshmeat.net/projects/dia/

I was taking a class where we were shown Visio, but I used Dia instead for my final project report. Not that this should influence your decision, but I did get an A in the class :)

ERW

[vigna]

Maybe you could find useful the stuff we developed for our internal usage: http://erw.dsi.unimi.it .

There is presently no graphical tool for editing diagrams--you must describe your schema using XML (we are working on graphical tool, but it is still, at best, immature).